The present disclosure relates to a color converting device, an image forming apparatus, and a color converting method for performing color conversion with a high degree of accuracy.
An image forming apparatus such as a multifunction peripheral (MFP) that prints character objects and image objects such as diagrams is a known art.
The image forming apparatus uses color values according to an RGB (Red, Green, Blue) color space as printing data. In contrast, the image forming apparatus typically uses color values according to a CMYK (Cyan, Magenta, Yellow, black/Key plate) color space when outputting (i.e., printing) to a recording sheet.
As a consequence, the image forming apparatus is required to convert color values in the RGB color space to color values in the CMYK color space in order to form (print) an image on the recording sheet.
Conversion from the RGB color space to the CMYK color space is performed using a color conversion table (i.e., a look-up table; LUT). In the color conversion table, a value in the CMYK color space corresponding to a value in the RGB color space is stored for each of a plurality of lattice points that partition the RGB color space at preset intervals. With regards to a color value in the RGB space for a point that is not one of the lattice points, a corresponding color value in the CMYK color space is calculated through interpolation calculation. The interpolation calculation is performed by linear interpolation or approximation-type interpolation.
In a known technique for increasing accuracy of color conversion, a color value is first converted to a cylindrical coordinate space and non-linear interpolation is performed using a spline function.